1062-3604/05/3604- © 2005 Pleiades Publishing, Inc.
Russian Journal of Developmental Biology, Vol. 36, No. 4, 2005, pp. 218–224. Translated from Ontogenez, Vol. 36, No. 4, 2005, pp. 265–273.
Original Russian Text Copyright © 2005 by Evgen’ev, Garbuz, Zatsepina.
The mechanisms providing for adaptation to unfa-
vorable environmental conditions have long attracted
attention of molecular biologists. The range of adapta-
tions is extremely wide and includes behavioral reac-
tions, as well as physiological and molecular-biological
mechanisms elaborated in the course of long-term evo-
lution. The range and signiﬁcance of individual adap-
tive reactions should differ in different species and
under different environmental conditions. A radically
new approach to studying the adaptation under the
extreme conditions was developed in our laboratory
following the description in the 1970s of molecular
consequences of the heat shock.
HISTORY OF DISCOVERY, MAIN CLASSES AND
FUNCTIONS OF HEAT SHOCK PROTEINS
After the discovery of heat shock (HS) proteins in
in the middle of 1970s, active studies began
into the structure and functions of proteins of this class,
which were found in practically all studied species:
to man (Heat Shock…, 1982). In addition
to heat shock, synthesis of HS proteins (HSPs) can be
induced by a number of agents, including hypoxia, var-
ious chemicals, etc. (Lozovskaya and Evgen’ev, 1984;
Margulis and Guzhova, 2000). At present HSPs are
classiﬁed according to their molecular mass; they are
divided in several groups, which include a few
homologs with similar molecular masses, structure, and
functions. The main groups are: HSP100/Clp
(~100 kDa), HSP90, HSP70/DnaK, HSP60/GroEL,
HSP40/DnaJ, and low molecular weight HSP/
tallins (15–30 kDa) (Heat Shock…, 1982; Lozovskaya
and Evgen’ev, 1984; Margulis and Guzhova, 2000).
Expression of the genes encoding some HSPs is main-
tained in most organisms at the normal physiological
conditions at a low level or is altogether absent and
increases manifold in the presence of stress factors.
HSPs encoded by the genes with such a pattern of
expression are called inducible. Other genes encoding
HSP-like proteins and homologous to the inducible
genes by 50–70% are expressed under the normal con-
ditions at a sufﬁciently high level. These genes are
called constitutive, although their expression may
increase under the stress conditions.
It was known for a long time that HSPs determine
the capacity of cells to adapt to high temperature (up to
a certain limit) and other damaging factors. It was
shown in the experiments with high temperature effects
on cells that preliminary moderate HS allows the cells
to endure later a tougher heat shock, which is lethal
without preliminary shock. This phenomenon was
called inducible thermotolerance. Some experimental
data suggest that it develops due to the accumulation of
HSPs (Lozovskaya and Evgen’ev, 1984; Margulis and
Guzhova, 2000). Artiﬁcial increase in the level of
HSP70 due to constitutive expression of the HSP-con-
taining vectors transfected into the cells is also accom-
panied by the formation of a thermoresistant pheno-
Heat Shock Proteins: Functions
and Role in Adaptation to Hyperthermia
M. B. Evgen’ev*
**, D. G. Garbuz*, and O. G. Zatsepina*
* Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, Moscow, 119991 Russia
** Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow oblast, 142292 Russia
Received February 21, 2005
—The results are generalized of many-year studies into the adaptive role of heat shock proteins in dif-
ferent animals, including the representatives of cold- and warm-blooded species that inhabit regions with dif-
ferent thermal conditions. Adaptive evolution of the response to hyperthermia can lead to different results
depending on the species. The thermal threshold of induction of the heat shock proteins in desert thermophylic
species is, as a rule, higher than in the moderate climate species. In addition, thermoresistant species are often
characterized by a certain level of heat shock proteins in cells even at a physiologically normal temperature.
Although adaptation to hyperthermia is achieved in most cases without changes in the number of heat shock
genes, they can be ampliﬁed in some cases in termophylic species. The role of mobile elements in evolution of
the heat shock genes was shown and approach was developed for directional introduction of mutations in the
promoter regions of these genes.
: heat shock proteins, genes of heat shock proteins, adaptation, thermoresistance, promoter regions
of heat shock genes.
MATERIALS FROM THE CONFERENCE DEDICATED
TO THE CENTENARY OF B.L. ASTAUROV